Power Supply System and Method of Controlling Power Supply System

Abstract

A power supply system is a power supply system that performs charging and discharging between the power supply system and an external system. The power supply system includes a plurality of battery units and a controller. The plurality of battery units include a plurality of battery packs and a plurality of converters provided corresponding to the plurality of battery packs. The plurality of battery units are connected together in parallel. The controller controls the plurality of converters to charge each of the plurality of battery packs to a fully charged state. For each of the plurality of battery packs, the controller is configured to perform equalization control to equalize voltages of cells included in the battery pack when the battery pack is charged to the fully charged state.

What is claimed is: 
     
         1 . A power supply system that performs charging and discharging between the power supply system and an external system, the power supply system comprising:
 a plurality of battery units including a plurality of battery assemblies and a plurality of converters provided corresponding to the plurality of battery assemblies; and   a controller that controls the plurality of battery units, wherein   the plurality of battery units are connected together in parallel, and   the controller controls the plurality of converters to charge each of the plurality of battery assemblies to a fully charged state, and   for each of the plurality of battery assemblies, the controller performs equalization control to equalize voltages of cells included in the battery assembly when the battery assembly is charged to the fully charged state.   
     
     
         2 . The power supply system according to  claim 1 , wherein for each of the plurality of battery assemblies, the controller controls a converter of the plurality of converters that corresponds to the battery assembly so as to charge the battery assembly to the fully charged state whenever a predetermined period has elapsed since the battery assembly is charged to the fully charged state the last time. 
     
     
         3 . The power supply system according to  claim 1 , wherein
 the battery assembly includes a plurality of cells connected in series, and   each of the plurality of cells is an iron-phosphate-based lithium ion battery.   
     
     
         4 . The power supply system according to  claim 1 , wherein
 for each of the plurality of converters, the converter is diverted from a three-phase inverter, and   a battery assembly of the plurality of battery assemblies that corresponds to the converter is connected to each phase arm of the three-phase inverter.   
     
     
         5 . A method of controlling a power supply system that performs charging and discharging between the power supply system and an external system, wherein
 the power supply system includes a plurality of battery units including a plurality of battery assemblies and a plurality of converters provided corresponding to the plurality of battery assemblies, and the plurality of battery units are connected together in parallel,   the method comprising:   controlling the plurality of converters to charge each of the plurality of battery assemblies to a fully charged state; and   for each of the plurality of battery assemblies, performing equalization control to equalize voltages of cells included in the battery assembly when the battery assembly is charged to the fully charged state.